Protein-Bound Uremic Toxins from Gut Microbiota and Inflammatory Markers in Chronic Kidney Disease

Abstract

Objective: Protein-bound uremic toxins from gut microbiota tend to accumulate in chronic kidney disease (CKD) patients and are poorly removed by current dialysis techniques. These toxins induce inflammation and are associated with cardiovascular disease (CVD). The aim of this study was to report the relationship between uremic toxins and inflammatory and cardiovascular markers in CKD patients.

Design: This was a cross sectional study.

Subjects: Twenty-one nondialysis patients were included (43% men, 63.0 ± 7.8 years, glomerular filtration rate: 34.4 ± 12.5 mL/min) as well as 29 hemodialysis (HD) patients [58% men, 52.7 ± 10.3 years, time on dialysis 54 (31-94.5 months)].

Main outcome measure: Total levels of uremic toxins (IS, p-CS, and IAA) were assessed by high-performance liquid chromatography with fluorescence detection. C-reactive protein, Interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and calprotectin plasma levels were determined by immunometric assays.

Results: HD patients presented higher inflammatory markers and uremic toxins levels than nondialysis patients. IL-6 levels were positively correlated with IS (r = 0.49; P = .03), p-CS (r = 0.35; P = .04) and IAA (r = 0.36; P = .03). A positive correlation was also observed between MCP-1 levels with IS (r = 0.72; P = .001), p-CS (r = 0.48; P = .001) and IAA (r = 0.75; P = .0001). Linear regression showed that IS was an independent predictor for IL-6 and MCP-1 levels after adjustment.

Conclusion: Plasma uremic toxins were associated with higher IL-6 and MCP-1 levels in CKD patients, potentially playing a role in the development of CVD.